• 유기물자원화
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• 제19권1호
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• pp.93-101
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• 2011

본 연구는 소각 시스템에 적용되는 반건식 반응기의 모델링 연구를 수행 하였다. 전산유체역학(CFD)을 이용하여 반건식 반응기에서 속도분포 온도분포를 조사하여 반응기의 최적 운전 조건을 조사하였다. 본 모델에 사용된 반응기의 직경은 3 m 이며 높이는 9 m 이다. 반응기로 유입되는 연소가스의 양은 $6,125Nm^3/hr$ 이며 반응기 유입 가스의 온도는 493K 이다. 반응기에 유입되는 소석회 양은 151 kg/hr 이다. 반응기의 입구 형상이 변하면 반응기 내의 온도가 변하며 반응기 내의 가스속도는 0.48 m/sec 에서 1.17m/sec 였으며, 반응기 출구의 가스속도는 6.9에서 7.42m/sec 였다. 모델링 결과에 의하면 반응기 내의 평균 가스 속도와 출구에서의 평균가스 속도는 각각 0.489 m/sec와 7.424 m/sec 였으며, 반응기 출구 온도는 448 K 였다.

• 센서학회지
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• 제16권6호
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• pp.428-433
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• 2007

$SnO_{2}$-based thick film ethanol gas sensors were fabricated on alumina substrates and their ethanol gas sensing characteristics were investigated. The film sintered at $400^{\circ}C$ for 2 hrs. showed the highest sensitivity to ethanol gas and the sensitivity of the film to 1000 ppm ethanol gas in air was 97 % at an operating temperature of $250^{\circ}C$. The addition of $Fe_{2}O_{3}$ to $SnO_{2}$ enhanced the sensitivity by changing the type and number of surface acidic/basic sites.

• 수산해양기술연구
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• 제43권4호
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• pp.362-369
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• 2007

This paper was studied on the characteristics of acid resistance and thermal shock for epoxy coatings in the strong acidic environment. The exhaust gas system, such as a air preheater, desulfurization equipment, for industrial boiler is damaged by dew point corrosion. To protect the acid corrosion, the coating using nonmetal was applied. The electrochemical polarization test, acid resistance and thermal shock test for epoxy coatings were carried out. And the acid resistance and thermal shock characteristics, aspect, and electrochemical anti-corrosion characteristics for epoxy coatings in the strong acidic environment were considered. The main results are as followings: As the epoxy glass flake coating by acidic thermal shock was damaged to the crack, blistering and elution etc., the current density of epoxy glass flake coating is high. But the damage of epoxy metal complex coating by acidic thermal shock was not occurred. Therefore the characteristics of acid resistance and thermal shock for epoxy metal complex coating is better than those for epoxy glass flake coating.

• 약학회지
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• 제46권2호
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• pp.113-119
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• 2002

The composition of monosaccharides of acidic polysaccharide isolated from ethanol-insoluble and water-soluble fractions of red ginseng roots was analysed and its immunological activities were investigated. Red ginseng acidic polysaccharide (RGAP) was composed of glucose (26.1 mole %), arabinose (1.6 mole %), glucuroninc acid (51.8 mol %) and galacturonic acid (5.1 mole %) as determined by gas liquid chromatography. Addition of RGAP increased production of nitric oxide (NO) and tumor necrosis factor (TNF)-$\alpha$ in the rodent macrophage cultures. Peritoneal macrophages from RGAP-treated mice exhibited potent tumoricidal activities toward P815 and WEHI 164 tumor cells. It was also observed that concentrations of NO and TNF-$\alpha$ were high in the culture medium of macrophages from the mice administered with RGAP. Moreover, treatment of RGAP in vivo stimulated tumoricidal activities of natural killer (NK) cells. Treatment with RGAP increased life span of sarcoma 180-bearing mice and decreased tumor weights of B16-tumor-bearing mice. These results suggest that activation of macrophages and NK cells serve to enhance in vivo anticancer activities of RGAP.

• 자원환경지질
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• 제48권1호
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• pp.89-101
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• 2015

'사워(sour)'는 종종 게르만 단어 "sauer 혹은 acidic" 어원에서 유래되었다. 사워가스는 물과 혼합되었을 때 산을 형성하는 황화수소($H_2S$)와 이산화탄소($CO_2$)와 같은 구성요소를 포함하고 있는 천연가스를 의미하며, 이는 부식, 연소와 폭발이 심하게 만드는 상당한 량의 황화수소를 포함하고 있으므로 사워가스 처리에 있어서 소요경비가 많아 들며 위험성이 따른다. 즉 특별한 취급과 기반시설을 요구하는 사워가스 사업은 가스의 경제적 가치와 생산 방법에 의한 요인으로 부터 영향을 받으므로 사워가스 개발생산은 안전하고 환경 친화적인 방법을 유지할 수 있는 진정한 과제들을 가지고 있다. 사워가스 에너지는 천연가스 중에서 황화수소 농도가 4 ppm 이상의 농도를 포함하고 있는 가스에 사용되는 용어로서 지하 심부의 돌로마이트 및 석회암 내에 부존하고 있다. 한편 황화수소는 부식될 수 있으며, 아주 낮은 농도에서도 사람에게 해롭기 때문에 특별한 주의가 필요한 위험한 가스이다. 계속적인 기술진보, 에너지 수요 급상승 및 유가강세는 미개발된 천연가스 중에서 40% 정도로 추정되는 사워가스 계획이 개선된 경제를 주도한다. 세계에서 사워가스 부존국가는 중국, 러시아, 캐나다, 미국 등등으로서 최대 부존지역인 중동지역으로서 부존된 천연가스 중에서 60%가 사워가스이고 다음은 최대 천연가스 생산국인 러시아로서 총 매장량의 34%가 사워가스이다. 세계 최대의 사워 가스전의 대부분 개발은 중동지역에 있는 오만, 쿠웨이트, 사우디아라비아와 아랍 에미리트 연방에서 착수를 하였다. 따라서 사워가스 자원 현황과 'Web of science' 데이터베이스에 등록된 학술문헌지에 발표된 사워가스 연구 활동(2000~2014)을 분석한 결과, 145편이 확인되었으며, 선도적으로 협력관계를 유지하는 기관은 미국지질조사소, 캐나다 지질조사소 및 중국 탐사개발 기술연구소이며, 국제적인 국가협력관계 측면에서는 중국, 미국 및 캐나다가 강세를 보여주고 있다.

• 한국안전학회지
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• 제35권6호
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• pp.85-92
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• 2020

Wet Scrubber reacts the incoming pollutant gas with cleaning water (water + absorbent) to absorb pollutants and release the clean air to the atmosphere. Wet scrubbers and packed tower scrubbers using this principle are widely used in businesses that emit acid gases. In particular, in the etching process using hydrochloric acid (HCl), alkaline washing water (NaOH) having a pH of about 8 to 11 is used to absorb a large amount of acid gas. However, These salts are attached to the injection nozzle (nozzle), filling material (packing), and the demister (Demister), causing air pollution, human damage, and inoperability due to clogging and acid gas discharge. Therefore, In this study, an improvement plan was proposed to manage the washing water with pH 3~4 acidic washing water. The test method takes samples from the Wet Scrubber flue measurement laboratory twice a month for 1 year. Hydrogen chloride (HCl) concentration (ppm) was measured, and nozzle clogging and scale conditions were measured, compared, and analyzed through a differential pressure gauge and a pressure gauge. As a result of the check, it was visually confirmed that the scale was reduced to 50% or less in the spray nozzle, filler, and demister. In addition, the emission limit of hydrogen chloride in accordance with the Enforcement Regulation of the Air Quality Conservation Act [Annex 8] met 3 ppm or less. Therefore, even if the washing water is operated in an acidic pH range of 3 to 4, it is expected to reduce air pollution and human damage due to clogging of internal parts, and it is expected to reduce maintenance costs such as regular cleaning or replacement of parts.

• Corrosion Science and Technology
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• 제5권1호
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• pp.5-14
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• 2006

A lot of parts in FGD (Flue Gas Desulphurization) systems of fossil-fuel power plants show the environments in which are highly changeable and extremely acidic corrosive medium according to time and locations, e.g. in duct works, coolers and re-heaters etc.. These conditions are formed when system materials are immersed in fluid that flows on them or when exhausted gas is condensed into thin layered medium to contact materials of the system walls and roofs. The environments make troublesome corrosion and air pollution problems that are occurred from the leakage of the condensed solution. The frequent shut-down and repairing works of FGD systems also demand costs and low efficiencies of those facilities. In general, high corrosion resistant materials have been used to solve this problem. However, even the super alloys and Teflon linings sometimes have not been good enough to preventing corrosion. Further more, they are expensive and not easily repairable in short periods of operation stops. In this work, new technology that is effective, economical and easily repairable has proposed to solve the corrosion problems in FGD facilities. This technology contains cathodic protection, coatings and remote monitoring-controlling systems.

• 한국대기환경학회지
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• 제17권2호
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• pp.193-201
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• 2001

Acidic air pollutants were collected to characterize indoor air quality in a residential area in the summer. All indoor and outdoor samples were measured simultaneously using an annular denuder system(ADS) in Seoul. The data set was collected from July 26 to September 11, 1997. The mean indoor/outdoor ratios measured from this study were : 0.34 for $HNO_3$; 0.91 for $HNO_2$; 0.22 for $SO_2$; 1.34 for $NH_3$; 0.78 for $PM_{2.5}(d_p$ <2.5 $mutextrm{m}$); 0.90 for $SO_{4}^{2-}$; 0.68 for $NO_{3}^{-}$ and 0.79 for $NH_{4}^{+}$. Indoor concentrations of $HNO_3$, $SO_2$ and $PM_{2.5}$ were highly correlated with the outdoor concentrations. The relationship between indoor and outdoor air is dependent, to a large extent, on the rate of air exchange between these two environments. A tracer-gas decay technique with sulfur hexafluoride ($SF_{6}$) as a tracer gas was used to estimate the air exchange of a private home in the summer. The average air exchange rate was estimated to be 23.7 hr(sup)-1. The deposition velocities for $SO_{4}^{2-}$, $NO_{3}^{-}$ and $NH_{4}^{+}$ calculated were 0.17, 0.69 abd 0.39 cm/sec, respectively.

• 공업화학
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• 제28권5호
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• pp.539-546
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• 2017

본 연구는 산성유해가스 제거를 위한 고효율 음이온교환 복합 폼 화학필터를 제조하기 위하여 폴리우레탄(PU) foam에 다른 종류의 PSA를 사용하여 상용이온교환수지를 부착하여 제조, 이의 내수성, 내화학성, 접착신율, 농도와 유속에 따른 HCl과 HF의 흡착특성에 관하여 연구하였다. 그 결과 접착신율은 ATE-701은 900%, AT-4000C는 1,500%, HCA-1000는 2,400%이며, 내수성 및 내화학성평가에서 HCA-1000의 탈리율이 6% 미만으로 우수한 내구성을 가짐을 확인하였다. HCl, HF의 농도와 유속이 증가함에 따라 흡착이 빠르게 일어났으며 유속과 농도에 관계없이 110 min 이후 100% 흡착파과평형이 일어남을 확인할 수 있었다. 또한 SEM Morphology 관찰 결과 점착제가 고르게 분산되어 있고 이온교환수지의 다공구조가 유지되었으며, 흡-탈착 공정에서 성능저하가 없는 것으로 보아 내구성이 있음을 확인하였다.

• Structural Engineering and Mechanics
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• 제84권6호
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• pp.733-741
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• 2022

The amount of natural gas that is used on a worldwide scale is continuously going up. Natural gas and acidic components, such as hydrogen sulfide and carbon dioxide, cause significant corrosion damage to transmission lines and equipment in various quantities. One of the fundamental processes in natural gas processing is the separation of acid gases, among which the safety and environmental needs due to the high toxicity of hydrogen sulfide and also to prevent wear and corrosion of pipelines and gas transmission and distribution equipment, the necessity of sulfide separation Hydrogen is more essential than carbon dioxide and other compounds. Given this problem's significance, this endeavor aims to extend the lifespan of the transmission lines' pipes for gas and oil. Zinc oxide nanoparticles made from the environmentally friendly source of Allium scabriscapum have been employed to accomplish this crucial purpose. This is a simple, safe and cheap synthesis method compared to other methods, especially chemical methods. The formation of zinc oxide nanoparticles was shown by forming an absorption peak at a wavelength of about 355 nm using a spectrophotometric device and an X-ray diffraction pattern. The size and morphology of synthesized nanoparticles were determined by scanning and transmission electron microscope, and the range of size changes of nanoparticles was determined by dynamic light scattering device.